Closure control mechanism



p 23, 1958 c. BRANDON ETAL CLOSURE CONTROL MECHANISM Filed July 13, 1956 J 7 RM M mm. e w Z e A r qT 2 i B 41 United?v State 2,853,158 cLosUnE CoNrRoL MEonANrsM Application .luiy 13, 1?56, Serial No. 597,768

1 Claim. (Cl. 137,-43}v T he present invention relates to a closure controlmechsm and more particularly to a control mechanism or dptable for use in controlling the opening and closing incitement of elevator doors or the like.

'ith the advent of modern automatic elevators, i; e. evatiors operable without an operator, elevator service een generally improved. However, one frustration This involves the closure of the elevator doors 22s n ritending passenger hurries toward the elevator to card the same. Once the doors are closed, the passenger ntil the next elevator stops upon signal. Thus, ve ence of shouting to the operator of the old style perated elevator is missing. em invention now proposes a closure control cc anisnr or system which will avoid this frustrating experience. The mechanism of the present invention utilizes an electric eye system to detect the approach of an intended passenger to prevent the closure of the doors until after the passenger has had an opportunity to board the elevator.

More specifically, the present invention proposes the utilization of a light source and a photoelectric cell positioned at the elevator location, either upon the elevator itself or in juxtaposition thereto, the light-from the source being reflected from a floor mounted reflector to fall upon the photoelectric cell. The cell is incorporated in a timing circuit so that, if the beam of reflected light upon the cell is uninterrupted for a short interval of time, the doors will close and the elevator will proceed to its next destination. However, if the light beam is interrupted by the approach of an intending passenger, closure of :the doors will be delayed until the passenger has had anopportunity to board the elevator.

The present invention also proposes a specific form of reflector which has been found to be particularly useful when utilized in such a control mechanism. Generally, the reflector may be described as a multi-facet reflector l or mirror which is embedded in the floor of the building immediately in front of, and preferably centrally of, the elevator door opening. The facets of the prism are disposed beneath the floor surface to prevent injury to the reflector and to avoid interference with open and unobstructed approach to the elevator. The facets are oriented, both horizontally and vertically, with respect to i the elevator, to provide a substantially continuous lightreflecting surface which will accurately reflectlight'from the source to the photoelectric cell, even though the exact stop height of the elevator may vary substantially.

Thus, the present invention provides a new and improved closure control mechanism, specifically adapted for utilization in connection with automatic elevators, and which is elfective to delay the closure of a door upon the entrance of an intending passenger within a zone through which the passenger must passin order to board the elevator. Additionally, this control mechanism occupies no useful floor space and does not obstruct the approach of the passenger to the elevator. One other advantage of the present invention is that variations in the stop height of the elevator are accommodated without interference with the closure control mechanism. Further, the light source and the photo-electric cell are mounted on and movable with the elevator, so that only one source and one cell are necessary per elevator.

It is, therefore, an important object of the present invention to provide an improved closure control mechanism for an elevator.

Another important object of this invention is the provision of a closure control mechanism including a source of radiation, a radiation sensitive cell, and a reflector operatively interposed between the source and the cell and cooperating therewith to define an encompassed area which, if trespassed by one intending passage through the enclosure, will alfect the operation of the closure mechanism.

It is a further object of this invention to provide an improved closure control mechanism. for an elevator wherein light from a source is reflected onto a light sensitive cell by means of a reflector positioned so that either the primary beam of light from the source to the reflector or the secondary beam of light from the reflector to the photoelectric cell mustbe intercepted by any intending passenger to delay closure of the door'.

It is a still further object of this invention to provide an improved closure control mechanism for an automatically operable elevator door including a" multi-facet reflector adapted to receive a primary beam of'light from a light source and to reflect thev beam to a light-sensitive cell, the reflector being located relative to the elevator so that the multiple facets thereofpresent a substantially continuous reflecting surface effective to reflectlight onto the cell regardless of substantial variations in the stop height of the elevator.

An additional important object is theprovision of a closure control for an elevator door comprisinglaterally spaced and fixed light-emitting and light-sensitive elements located adjacent the extremities of the elevator door and a reflector buried in the floor exteriorly of the elevator and oriented with respect to the elements to reflect light therebetween, the reflector having a plurality of parallel facets each of which lies substantially normal to a plane passing through the refracted primary and reflected beams, the facets cooperating to define the equivalent of a substantially continuous reflecting surface of sufficient extent to accommodate normal tolerances in the floor leveling mechanism of the elevator.

These and other objects will be more apparent from the following detailed description of a preferred embodiment of this invention and by reference to the drawings forming a part hereof wherein:

On the drawings:

Figure 1 is a schematic elevational Vi6W illustrating the general arrangement of a closure control mechanism of the present invention;

Figure 2 is a plan view of a multi-facet present invention; and

Figure 3 is a sectional view taken along the'plane 33 of Figure 2.

As shown on the drawings:

In Figure 1, reference numeral 10 refers generally to a conventional elevator which is vertically movable in fixed guides of trackwaysby the'usual elevator actuating mechanism (not shown).

prism of the The elevator is provided with a plurality of laterally slidable doors, indicated in dotted outline at 11, which are openable to expose the interior of the elevator through an open doorway, indicated generally at 12. Located in the opening 12 adjacent the lateral extremities of the opening, so as to be exposed when the door is opened, is a source 13 of radiation, such as visible light rays. The light source 13 may conveniently be an incandescent bulb having a focusing housing or lens effective to concentrate the light into a beam 14. Also carried by the elevator at the other side of the opening 12 is a radiation-sensitive device, such as a photoelectric cell 15.

It will be noted that the primary beam 14 issuing from the source 13 passes through the doorway 12 to impinge upon a reflector 16, the reflector being oriented so that the beam of light 14 is reflected, as at 17, in a path to impinge upon the photoelectric cell 15.

As best illustrated in Figures 2 and 3, the reflector 16 is generally cylindrical in exterior contour and is embedded in a cylindrical recess 19 in the floor 18 of the building. The reflector is provided at its lower surface with a plurality of reflective facets or surfaces 20 which are mirrored, aluminized, or otherwise treated so as to readily reflect the primary light beam 14. Joining, angularly disposed faces 21 lie substantially normal to the reflective facets 20, for a purpose to be hereinafter more fully described.

As best seen in Figures 1 and 3, the reflector 16 is preferably installed in the floor medially of the opening 12 and in advance thereof. The source 13 and the cell are preferably mounted adjacent the upper reaches or extremities of the elevator 10, so that a downwardly extending primary beam 14 and an upwardly extending secondary beam 17 are formed. These beams cooperate to define an area immediately in advance of the elevator door opening which can be entered only by interrupting either the primary beam 14 or the secondary beam 17. Thus, the amount of light falling upon the photoelectric cell 15 will be reduced by the passage of an intending passenger toward the elevator opening. The photoelectric cell 15 is incorporated in the door opening timing circuit for the elevator door and, so long as the primary beam 14 and the secondary beam 17 are not interrupted, the doors are closed after the normal interval of time. However, upon the interruption of one or the other of the beams of light, the timing cycle is also interrupted and the doors will not be closed until the end of a second timing cycle which is suflicient in duration to accommodate the entry of the passenger into the elevator.

The orientation of the facets with respect to the source 13 and the cell 15 are best illustrated in Figure 3 of the drawings, in which it will be seen that these facets each lie substantially normal to the projected path of the beam 14, as refracted during its passage through the reflector, as at 22. The more dense material of the reflector, such as glass, will cause refraction of the beam, and this refraction is accommodated by the orientation of the facets. The reverse refraction, of course, occurs upon issuance of the reflected beam from the reflector material, but since the primary refracted beam 22 lies normal to the facets as viewed in the projection of Figure 3, and when viewed in this fashion, the reflected beam will travel along the same course as the indicated paths of the refracted beam 22 and the primary beam 14.

The reflective facets 20 are parallel and the reflector is of substantial extent so that the adjusted vertical position of the elevator, within certain limits, such as normal variations in stop height of an automatic elevator, will not interfere with the reflection of the primary beam in the proper path for reception by the cell 15. In other words, if the stop height varies, the primary beam 14 will merely be shifted to the right or to the left, as indicated in Figure 3 of the drawings, and the refracted beam will strike a different facet from that specifically illustrated in Figure 3. However, the facets being parallel,

the same reflection in the same direction will occur in a path parallel to but vertically displaced from the beam shown in Figure 3. The joining faces 21 lie preferably normal to the facet 2t) and parallel to the refracted primary beam, so that they will not interfere with the beam striking one of the reflective facets.

It will be readily appreciated by those skilled in the art that the present invention proposes a new and novel closure control mechanism wherein light from a source is reflected onto a light sensitive cell or similar device to delay the closure of an elevator door until such time as an intending passenger intercepting one of the light beams has had an opportunity to board the elevator. The use of a source and a cell fixed with respect to the elevator and with respect to one another, plus the use of the multi-facet reflector, makes possible the accommodation Further, the

of variations in the elevator stop height.

use of a reflector at each floor level, defining a triangular r entrance area in front of the elevator will be understood to be more efficient in preventing premature door closure on an incoming passenger than a beam directly across the elevator entrance.

The positioning of the reflector relative to the source and the photoelectric cell is accomplished as follow ,5

The height of the source and of the cell is fixed,.= .v'v' relation to the floor of the elevator and the normalistop height of the elevator, at a height such that the primary I and secondary beams will be intercepted by aperflt approaching the elevator and passing between the For example, the cell and thesouroe; may preferably be located about 5 feet aboveiflieaek vator floor and adjacent the respective lateral w and the reflector.

of the elevator opening.

Assuming that the reflector is to be centrally M i .1. the location and angularity of the reflective faoets reliive, l" to the horizontal can be determined by establishing vertical plane of the primary beam and the point of inter-" section of this plane with the free upper surface of the reflector. The point of entry of the beam plane into the glass reflector is thus established. The beam will be refracted in the beam plane to an extent determined by the refractive index of the reflector material and the angle of entry of the beam. The actual refractive path of travel of the beam can be determined and the point located at which the refracted beam strikes the reflective surface. If the reflective surface were positioned so as to be normal to the actual line of refracted beam travel, the beam would merely be reflected back to the source.

To reflect the beam to the cell, the reflective facets must be normal to the actual line of refracted beam travel as projected onto a vertical plane bisecting the included angle between the primary and reflected beams. When the reflector is centrally located, such a vertical plane lies midway between the source and the cell and normal to the lateral vertical plane of the opening. The actual line of refracted primary beam travel is merely projected into the vertical bisecting plane and the reflective facets are oriented so as to lie normal to this projected refracted beam.

While preferred embodiments have been described above in detail, it will be understood that numerous modifications might be resorted to without departing from the scope of our invention as defined in the following claim.

We claim:

In a door control mechanism for an elevator movable vertically relative to a floor and wall opening leading to the elevator, a light beam source on the elevator at one lateral extremity of its entrance, a light sensitive cell on the elevator at the other lateral extremity of its entrance, and a reflector installed in said floor medially and substantially outside of said wall opening in a position to reflect said beam to said cell when the elevator is in an open receiving position at said floor and for beam interruption either before or after reflection by an approaching References Cited in the file of'this patent UNITED STATES PATENTS Lucas Nov. 8, 1932 Ellis Feb. 13, 1934 Bone July 29, 1941 Patton Dec. 21, 1943 

